Problem/Motivation
The Layout Builder uses core's off-canvas "tray" when adding/editing blocks to a layout. It opens the tray on the right side of the page, but it's not very wide, and as a result it doesn't accommodate larger block forms very well. This is most evident when adding block that has a textarea field w/ CKEditor:
This problem surfaced in #2948064: Layout Builder should support inline creation of Custom Blocks using entity serialization.
An interesting issue to follow that may help resolve this is #2916781: Allow off-canvas dialog to be rendered at the top of the page.